BRPI0716332B1 - method and apparatus for sending channel quality indication through a shared channel - Google Patents

Abstract

method and apparatus for sending a channel quality indication by means of a shared channel a method and apparatus for sending a channel quality indication (cqi) by means of a shared channel as a transmission and reception unit are described wireless (wtru) is in a cell_fach state without having a dedicated channel allocated to wtru. a wtru performs a measurement of at least one parameter and generates a cqi based on the measurement. wtru then transmits the cqi through a random access channel (rach). cqi can be transmitted using a crack preamble. a series of signature strings can be divided into a series of groups. wtru can select a group based on cqi and randomly select a signature string from among the signature strings in the selected group to transmit the preamble to the split. the cqi can be attached to the crack preamble. cqi can be transmitted via a control part or a data part of the crack message

Description

(54) Title: METHOD AND APPARATUS FOR SENDING THE CHANNEL QUALITY INDICATION THROUGH A SHARED CHANNEL (51) Int.CI .: H04L 5/00; H04L 25/02; H04L 29/08; H04W 08/24; H04W 24/10; (...)

(52) CPC: H04L 5/0057; H04L 1/0026; H04L 25/0222; H04L 69/323; H04W 08/24; (...)

(30) Unionist Priority: 05/02/2007 US 60 / 888,146; 10/23/2006 US 60 / 862,522; 03/28/2007 US 60 / 908,484.

(73) Holder (s): INTERDIGITAL TECHNOLOGY CORPORATION.

(72) Inventor (s): ROCCO DIGIROLAMO; PAUL MARINIER; SUDHEER A. GRANDHI; VINCENT ROY; CHRISTOPHER R. CAVE.

(86) PCT Application: PCT US2007022311 of 10/19/2007 (87) PCT Publication: WO 2008/051466 of 02/05/2008 (85) Date of the Beginning of the National Phase: 23/04/2009 (57) Summary: Method and apparatus for sending channel quality indication by means of a shared channel A method and apparatus for sending a channel quality indication (CQI) by means of a shared channel are described as a transmission and reception unit wireless (WTRU) is in a Cell_FACH state without having a dedicated channel allocated to the WTRU. A WTRU performs a measurement of at least one parameter and generates a CQI based on the measurement. The WTRU then transmits the CQI through a random access channel (RACH). CQI can be transmitted using a RACH preamble. A series of signature strings can be divided into a series of groups. The WTRU can select a group based on the CQI and randomly select a signature string from among the signature strings in the selected group to transmit the RACH preamble. The CQI can be attached to the preamble to RACH. The CQI can be transmitted via a control part or a data part of the RACH message

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METHOD AND APPARATUS FOR SENDING CHANNEL QUALITY INDICATION THROUGH A SHARED CHANNEL

FIELD OF THE INVENTION [001] The present invention relates to wireless communications.

BACKGROUND OF THE INVENTION [002] A wireless transmission and reception unit (WTRU) in a universal terrestrial radio access network (UTRAN) can be in an inactive or connected state. When the WTRU is in a connected state, based on the activity and mobility of the WTRU, the UTRAN can direct the WTRU to transition between the states Cell_PCH, URA_PCH, Cell_FACH and Cell_DCH. User plan communication between the WTRU and the UTRAN is only possible when the WTRU has a radio resource control (RRC) connection to the UTRAN.

[003] The Cell_DCH status is categorized by dedicated channels on the uplink and downlink. On the WTRU side, this corresponds to continuous transmission and reception and can be demanding in terms of user power needs.

[004] As defined in Version 6 of the specifications of the Third Generation Partnership Project (3GPP), the Cell_FACH state does not use dedicated channels and therefore allows better energy consumption at the cost of lower uplink and downlink performance. While in the Cell_FACH state, uplink communication is achieved via a random access channel (RACH) while downlink communication is accomplished via a shared transport channel (such as a frontal access channel (FACH)), mapped to a physical secondary common control channel (S-CCPCH). The Cell_FACH status is suitable for traffic signaling (such as transmission of UTRAN registration area update messages (URA) and cellular update and for applications that require very low uplink performance.

[005] While in the Cell_FACH state, the WTRU can perform signal measurements and / or traffic volume measurements (TVM) as specified in the measurement control information. Signal measurement is used by the WTRU for new cell selection. TVM is reported to UTRAN in a measurement report based on specified criteria on the measurement control information. The measurement report is sent via

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2/15 of the RACH.

[006] RACH is based on an Aloha mechanism with spaces with an indication of obtaining. Before sending a RACH message, a WTRU tries to obtain the channel by sending a short preamble (composed of a randomly selected subscription string) in a randomly selected access space. After the transmission of the RACH preamble, the WTRU awaits an indication of obtaining the UTRAN. If no retrieval indication is received, the WTRU raises the transmission power to the RACH preamble and retransmits the RACH preamble (that is, it sends a randomly selected signature string in a selected access space). If an acknowledgment is received, the WTRU has actually obtained a channel and can transmit a RACH message. The initial transmission power for the RACH preamble is defined based on an open circuit power control method and the lifting mechanism is used to fine tune the transmission power of the WTRU.

[007] It has been proposed to use high speed downlink (HSDPA) packet access in a Cell_FACH state. HSDPA is a feature that was introduced in Version 5 of the third generation partnership project (3GPP) specifications. HSDPA operates in a Cell_DCH state. HSDPA makes better use of the shared downlink capability using three fundamental concepts: adaptive modulation and coding (AMC), retransmissions using a hybrid automatic repeat request scheme (HARQ) and Node B programming.

[008] Every 2 (two) milliseconds, Node B schedules transmissions on the shared high-speed downlink channel (HS-DSCH) based on information collected by Node B of the WTRUs and the position of the downlink buffers. In addition, Node B adapts transmission bit rates to specific WTRUs by adapting the MCS, transport block size, etc. Node B can transmit at a higher data rate for WTRUs that perceive favorable channel conditions and at a lower data rate for WTRUs that perceive unfavorable channel conditions (such as at the cell end).

[009] For HSDPA operations, Node B needs an indication of the quality of

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3/15 channel (CQI) and positive recognition feedback (ACK) and negative recognition (NACK) of the WTRUs. The CQI is an index on a table that provides the maximum MCS that the WTRU can sustain. The CQI is sent periodically at intervals determined by UTRAN. ACK / NACK feedback is intended for the HARQ process. ACK / NACK information is only provided in response to receiving a package on the downlink.

[0010] In Version 6 of the 3GPP specifications, CQI and ACK / NACK information are transmitted through a dedicated high-speed physical control channel (HSDPCCH). Each WTRU is assigned a separate HS-DPCCH and, as a result, a WTRU can easily provide feedback information. In addition, the HS-DPCCH has controlled power using a compensation for the dedicated physical control uplink channel (DPCCH), for which closed-circuit power control is performed. HS-DPCCH information is heavily encoded to aid in detection. As more and more WTRUs use HSDPA, the number of feedback control channels increases. Even if they have controlled power, feedback information can cause uplink noise to rise, reducing the capacity available for other uplink transmissions.

[0011] If HSDPA is to be used in a Cell_FACH state, the main problem is the lack of a dedicated uplink channel to transmit the CQI and ACK / NACK information. Without CQI and ACK / NACK information, the advantages of HSDPA are significantly reduced. The 3GPP Version 6 specifications do not provide support for selecting the ideal MCS and programming for the HS-DSCH in a Cell_FACH state.

[0012] It would be desirable, therefore, to provide a method and apparatus for providing CQI information through a shared channel in a Cell_FACH state. SUMMARY OF THE INVENTION [0013] A method and apparatus for sending CQI through a shared or common channel while a WTRU is in Cell_FACH state which has a dedicated channel allocated to the WTRU are described. A WTRU performs a measurement of at least one parameter and generates a CQI based on the measurement. The WTRU then transmits the CQI via a RACH. CQI can be transmitted using a preamble

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4/15 RACH. A series of signature strings can be divided into several groups. The WTRU can select a group based on the CQI and randomly select a signature string from among signature strings in the selected group for transmission of the RACH preamble. The CQI can be attached to the preamble to RACH. The CQI can be transmitted via a control part or a data part of the RACH message. The RACH message can be an RRC measurement report that includes CQI transmission. The CQI report can be triggered by successfully decoding the HS-SCCH transmission.

BRIEF DESCRIPTION OF THE FIGURES [0014] A more detailed understanding of the present invention can be obtained from the description of a preferred embodiment below, provided as an example and to be understood together with the attached figures, in which:

Figure 1 is a block diagram of an example of a WTRU;

- Figure 2 shows a CQI attached to the end of a RACH preamble;

- Figure 3 shows an example of the CQI conducted in the RACH control message;

Figure 4 shows an example of the CQI conducted in the RACH header in a RACH message;

- Figure 5 shows an example of a CQI structure with two planes; and

- Figure 6 shows an example of triggering a report.

DETAILED DESCRIPTION [0015] When indicated below, the WTRU terminology includes, but is not limited to, user equipment (UE), mobile station, fixed or mobile subscriber unit, pager, cell phone, personal digital assistant (PDA) , computer, or any other type of user device capable of operating in a wireless environment. When indicated below, Node B terminology includes, but is not limited to, a base station, location controller, access point (AP) or any other type of interface device capable of operating in a wireless environment.

[0016] It should be noted that, although the achievements are described with reference to 3GPP high-speed downlink (HSDPA) packet access, the present invention is applicable to any wireless communication system where the

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5/15 transmission of channel quality feedback information through a common / shared channel.

[0017] Figure 1 is a block diagram of an example WTRU 100. The WTRU 100 can include a measurement unit 102, a CQI generator 104 and a transceiver 106. It should be noted that WTRU 100 in Figure 1 is provided as an example, not as a limitation, and the WTRU 100 can include any other conventional processing components required for wireless transmission and reception. The measurement unit 102 performs a measurement of at least one previously determined parameter to provide an estimate of the channel quality perceived by the WTRU 100.

[0018] The measurement parameter can be a block error rate (BLER) of the downlink transport channel while the WTRU 100 is in the Cell_FACH state. A high BLER can be interpreted as the downlink transmission speed being too high. The measurement parameter can be a path loss measured on a downlink reference channel (such as a common pilot channel (CPICH)). A high loss of path in the downlink can be interpreted as an indication that the downlink transmission speed is too high. The measurement parameter can be the number of preamble elevations required before receiving a take indication in a take indication channel (AICH). If the WTRU 100 requires many increases in the transmission power of RACH preambles or, if the RACH transmission fails, the WTRU 100 can interpret that the channel conditions are poor and request a reduction in the downlink transmission speed. The measurement parameter can be a power received at a CPICH, a high-speed shared control channel (HS-SCCH) or any downlink reference channel. By providing an indication of this power, Node B can estimate the lost path and increase or decrease the downlink transmission speed proportionally. The measurement parameter can be an estimate of a signal-to-noise ratio (SNR) measured on any downlink reference channel (such as CPICH), where the noise comprises thermal noise and interference from neighboring cells that cannot be canceled by the WTRU. The measurement parameter can be CPICH Ec / N0 (ie power

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6/15 of signal code received from CPICH (RSCP) / received signal strength indicator (RSSI)) or primary common control physical channel RSCP (PCCPCH) converted to HS-DPDCH measurement by adding RSSI. Alternatively, the power of HS-SCCH can be measured.

[0019] The CQI generator 104 issues a CQI based on the measurement (s) (ie, the CQI is a coded version of the measurement). One or a combination of any of the WTRU measurements above can be mapped to a CQI value (such as an index to a lookup table) and sent to Node B via one of the feedback mechanisms that will be described in detail below. The CQI value can be sent to an RRC layer for reporting in the RRC layer. The CQI value can be filtered on the RRC layer. When performing the mapping, the WTRU 100 can also consider its own receiving capabilities to generate a CQI.

[0020] The CQI is not necessarily a linear encoding of the measurements, but it can also be an estimate of the transport block size or a maximum data speed that the WTRU 100 can sustain based on its receiver design and the measured quantities ( that is, the CQI can be a coded version of a transport block size or the maximum data speed that the WTRU can sustain to maintain a target block error rate (BLER) .The maximum transport block size or the maximum data speed that can be sustained by the WTRU is formatted and encoded in an index value (ie CQI value).

[0021] Alternatively, the CQI can be a relative up or down command generated based on the measurement. The relative up or down command can be generated based on a transport block size that the WTRU can hold to maintain a target BLER. The WTRU 100 may decide, for example, that the channel quality is very low and request a reduction in the downlink transmission speed to the next lowest level. In this case, the granularity of the control can be more than one step (such as three levels up, four levels down). The relative up or down command can indicate an increase or decrease in the maximum transport block size that the WTRU 100 can receive with a suitable BLER or an increase or decrease in a measured value (such as in dB) on a channel (such as

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7/15 lost track).

[0022] CQI may have a structure with several plans. Figure 5 shows an example of a CQI structure with two planes. It should be noted that Figure 5 is provided as an example, not as a limitation, and any other CQI framework can be implemented. In this example, the CQI value is encoded with 5 (five) bits. The first two most significant bits (MSBs) are used as a raw CQI and the three least significant bits (LSBs) are used as a fine CQI within each range of raw CQI. The CQI report via the RRC measurement report can be used to send the raw CQI (slow update) and the physical layer procedure (L1) can be used to send the thin CQI (fast update). In a slowly changing channel condition, gross CQI can be used, while if the CQI change speed is higher, CQI can be reported using the L1-based CQI reporting procedure.

[0023] After the generation of the CQI, transceiver 106 transmits the CQI to Node B. Since there is no dedicated control channel assigned to WTRU 100 in a Cell_FACH state, transceiver 106 sends CQI information via a RACH or any other contention-based channels that require the WTRU to obtain the channel first before starting the transmission.

[0024] The CQI transmission provides new and appropriate link performance predictors for transmissions on the HS-DPDCH. The CQI can be sent when the WTRU has previously been in a URA_PCH or Cell_PCH mode, no measurements have been taken and therefore no measurements are available to the UTRAN. The CQI can be reported when the WTRU has sent at least one measurement value to the UTRAN, but it still needs to receive any downlink transmission. CQI can be reported when the WTRU has received transmissions for some time, but the measurements are out of date. In the latter two cases, the number of measurement controls required on the HS-DSCH is reduced.

[0025] Achievements for sending the CQI are described below. According to a first embodiment, the WTRU 100 sends the CQI information using a RACH preamble. Conventionally, a WTRU selects a preamble signature sequence from

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RACH randomly among a series of signature strings. According to the first realization, the signature strings are divided into a series of groups. The WTRU 100 selects a group based on the CQI and then randomly selects a signature string from among the signature strings in the selected group. The selection of the signature string is not completely random, but depends on the CQI. If a 2 (two) bit CQI is used and a total of sixteen signature strings is divided into four groups, each with four unique signature strings, for example, the CQI can be used to select one of the 4 (four) groups and one of the four signature strings in the selected group is selected at random. When decoding the signature sequence at Node B, Node B cross-references the signature sequence number to determine the group and the transmitted CQI.

[0026] If the number of CQI indexes exceeds 16, the number of conventional sixteen-bit preamble signature strings can be increased from 16 to 2k (where k> 4) and, instead of repeating the selected signature string 256 times in each preamble, the WTRU 100 can repeat the new signature sequence (256 / (2k4)) times.

[0027] Alternatively, a CQI can be attached to the end of the RACH preamble. Figure 2 shows a CQI 206 attached to the end of a RACH preamble 202. In this example, the transmission of the RACH preamble includes 256 repetitions of a signature sequence with sixteen bits 204 and a CQI 206. When Node B detects the sequence of preamble 202, Node B retrieves the CQI 206 at the end of the preamble sequence 202 and sends a fetch indication. The identity (ID) of the WTRU can be determined when Node B decodes the RACH message. Alternatively, the WTRU ID can also be attached to the end of the preamble. This allows for the transmission of all necessary information in the preamble without the need for a subsequent RACH message transmission.

[0028] As a second realization, a CQI is sent through the control part of the RACH message. Figure 3 shows an example of a RACH time slot format. A 10 ms 300 RACH radio board includes fifteen

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9/15 time 302. Each time slot 302 includes a data part 310 and a control part 320 which are transmitted in parallel. Conventionally, control part 320 carries pilot bits 322 and TFCI bits 324. As per the second embodiment, CQI 326 is included in control part 320.

[0029] According to a third realization, the CQI is sent via data part 310 of the RACH message. Figure 4 shows an example of a RACH 410 header and a MAC service data unit (SDU) 420 in a RACH 400 message. CQI 412 is included in the RACH 410 header. In order to include CQI 412 in the RACH 410 header, the physical layer provides CQI 412 to the MAC layer (MAC-c / sh layer) and the MAC layer adds CQI 412 to the MAC 410 header. Signaling between the physical layer and the MAC can be implemented, for example, using a modified PHY-Situation-IND primitive.

[0030] According to a fourth realization, the CQI can be sent via an RRC message (such as a measurement report message). The CQI is sent to the RRC layer of the WTRU for inclusion in the RRC message. The CQI can be optionally filtered by the RRC layer before sending the RRC message.

[0031] As the capacity of the physical RACH (PRACH) is limited, rules are defined to determine when the transmission of the CQI should take place. A WTRU can transmit the CQI when the WTRU has a MAC SDU to transmit through RACH (ie, opportunistic transmission). The CQI can be transmitted within the RACH preamble or the RACH message, as described above.

[0032] Opportunistic transmission may not be enough because it depends on the need to transmit information about the uplink when they are not necessarily correlated with downlink transmissions. To allow CQI reporting in the absence of uplink transmission on the RACH, the WTRU can transmit the CQI, even if the WTRU does not need to send a MAC SDU (ie, isolated CQI transmission). The TFCI field can be used to signal to Node B that the RACH transmission is an isolated CQI transmission. For isolated CQI transmissions, a CQI can be attached to the RACH preamble as shown in Figure 2 or it can be transmitted in the control or data part of the RACH message.

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10/15 [0033] Alternatively, triggering criteria for CQI transmission (that is, isolated CQI transmissions) can be defined. A CQI can be transmitted periodically. The WTRU can send the CQI periodically when the WTRU has an active HSDPA connection in a Cell_FACH state. The WTRU can continuously monitor the channel condition and send the CQI at periodic intervals. The CQI reporting speed is provided to the WTRU in the form of a configuration parameter. CQI can be reported with random compensation to reduce the likelihood of a collision between WTRUs.

[0034] A CQI can be gathered by Node B. The WTRU can transmit, for example, a CQI upon receipt of data on the downlink. Node B can select a low MCS or not transmit any data in that initial downlink transmission (in order to reduce interference) if Node B does not have new CQI information. The downlink transmission can be a transmission on an HS-SCCH destined for the WTRU. In this case, the WTRU monitors the HS-SCCH and triggers the CQI transmission when the WTRU successfully decodes its address (ie HSDPA radio network temporary identity (HRNTI)) in the HS-SCCH transmission on the downlink.

[0035] The WTRU can send a CQI upon significant change in the channel conditions. The WTRU can transmit a CQI when the difference between the current CQI (or average CQI) and the last reported CQI exceeds a previously determined value. The WTRU (such as RRC) is configured with a CQI delta. Whenever the measured value of the CQI exceeds the previous value of the CQI by the CQI delta for a previously defined period of time, a CQI report is triggered.

[0036] The WTRU can send a CQI at the beginning of an HSDSPA connection in a Cell_FACH state. The WTRU can continuously monitor channel conditions, but the CQI can be sent after receiving an RRC CONNECTION CONFIGURATION message for the HSPDA channel.

[0037] The CQI range can be divided into several levels of CQI with CQI limits and the WTRU can send a CQI based on the comparison of the measured (or filtered) CQI with the CQI limits. If the measured (or filtered) CQI exceeds a CQI limit (that is, change the CQI level) and remains at the new CQI level for a period of time

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11/15 previously defined, a CQI report is triggered. Figure 6 illustrates an example of triggering CQI based on comparison to CQI limits. It should be noted that Figure 6 is provided as an example and not as a limitation and the CQI range can be divided into any number of levels. In this example, two CQI limits are set and the CQI range is divided into three levels (CQI1, CQI2 and CQI3). Initially, the measured CQI belongs to the CQI1 level. At time A, the measured CQI is changed to the second level, CQI2. At that time, a timer is set to trigger the CQI report. The measured CQI remains at the CQI2 level until the timer expires and, therefore, a CQI report is triggered when the timer expires. At time B, the measured CQI is changed to the CQI1 level and the timer is reset. The measured CQI is changed to the CQI2 level before the timer expires. A CQI is therefore not sent at this time. At time C, the measured CQI is changed to the CQI3 level and the timer is set. The measured CQI remains at the CQI3 level until the timer expires and a CQI report is triggered when the timer expires.

[0038] The CQI report can be triggered based on certain actions of the WTRU. The CQI can be sent, for example, when the WTRU is changed to the Cell_FACH state and / or by means of a new cell selection in the states Cell_FACH, Cell_PCH and URA_PCH.

[0039] The CQI report can be triggered based on the downlink receipt (as sent when the WTRU stops decoding the downlink receipt) and the CQI can be sent along with RRC and / or control ACK / NACK information radio links (RLC). The speed of triggering CQI reports can be adjusted based on NACK counts. The reporting speed increases as the NACK counts increase and the reporting speed decreases as the ACK counts increase.

[0040] The CQI report can be triggered based on BLER HARQ, when no control information or data (ie HS-SCCH transmissions) is received when expected, based on transport block BLER.

[0041] The CQI report can be triggered based on the receipt of HS-SCCH. After successful decoding of an HS-SCCH transmission, the WTRU expects data transmissions on the associated HS-PDSCH. After correctly decoding a

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12/15 HS-SCCH transmission, if the WTRU is not able to recover the HSPDSCH transmission, the CQI report can be triggered. This triggering mechanism can be based on an average calculation window, in such a way that the CQI report is triggered after M occurrences among N observations. M and N can be coded or configurable over the network.

[0042] Alternatively, the CQI report can be triggered by counting the number of successful HS-SCCH transmissions (K) in an observation window. The observation window starts with the first decoding of the HS-SCCH transmission with a new data indicator that indicates a new transport block. The observation window should be large enough to include all the expected retransmissions for each transmitted packet. The observation window can be closed when the next HS-SCCH transmission arrives with a new data indicator. The CQI is triggered when K is less than the maximum number of retransmissions configured for HSDPA in Cell_FACH. The K value and the size of the observation window can be configured over the network. The trigger can be based on an averaging window.

[0043] Alternatively, the CQI report can be triggered after correctly decoding the HS-SCCH transmission and retrieving the packet transmitted on the HS-PDSCH after L retransmissions, where L is less than the maximum number of retransmissions configured for HSDPA in Cell_FACH. The L parameter can be coded or configurable over the network. This event indicates that the current MCS is very conservative. The trigger can be based on an averaging window.

[0044] The CQI report can be triggered based on the inactivity of HS-SCCH. The WTRU can start a timer after decoding an HSSCCH transmission and trigger the CQI report if the WTRU stops receiving any HSDPA transmission until the timer expires. The timer value can be coded or configurable over the network.

[0045] The limit values and timer values described below can be defined as part of the system information. The limit and timer values can be set again. To reduce the burden of downlink signaling for

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13/15 specify these new limit and timer values by means of RRC signaling, the limits and timer values can be changed autonomously by the WTRU based on RRC and / or RLC ACK / NACK information. Limit values can be linear, asymmetric or logarithmic (which have finer granularity for certain levels at the expense of others). The limit values can be changed independently by the WTRU based on BLER HARQ.

[0046] The CQI report can be controlled by means of downlink control signaling in a Cell_FACH state. The downlink control signal can be sent via an HS-SCCH, a MAC-hs header, a physical layer signal, an L2 control channel on the downlink etc.

[0047] The transmission of CQI through RACH can be configured by signaling the upper layer (such as signaling layer 3). This configuration includes the signature strings that the WTRU should use to transmit the RACH preamble, the time slot format, encryption and channel codes that the WTRU should use to transmit the PRACH and the like.

[0048] The network can learn about the capabilities of different WTRUs and determine whether a WTRU is capable of sending a CQI via PRACH / RACH. The network can send configuration parameters to the WTRU based on the capacity of the WTRU. Configuration parameters can be sent by adding new information elements (IEs) to a conventional system information block (SIB) in a BCCH, defining a new SIB (and programming) in BCCH or adding an IE to the RRC CONNECTION CONFIGURATION message when the HSDPA channel is configured. The new measurements can fit into the Quality Measurements category and can be applied to WTRUs in Cell_FACH status. Configuration parameters include a method of sending CQI information (in RACH, using an L1-based approach, using raw or fine CQI and the like), CQI reporting parameters, CQI filter coefficients (for layer filtering 3 CQI value), CQI reporting criteria (ie limit and timer values) and the like.

[0049] For backward compatibility, Node B may be aware that a WTRU is sending a CQI via a RACH (ie, the RACH transmission includes a

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CQI). In order to differentiate RACH transmissions that include a CQI, new signature strings can be defined or certain signature strings are reserved for CQI reporting purposes, so that Node B can differentiate a RACH transmission that includes a CQI and a RACH transmission that does not include a CQI. Alternatively, one or more values of the TFCI field of the control part of the RACH message (or any field in the RACH header) can be reserved for RACH transmissions that include a CQI. Alternatively, a set of encryption and channeling codes can be reserved for RACH transmissions that include a CQI.

[0050] The present invention is applicable to a WTRU in Cell_PCH and URA_PCH states. In these states, the measurements used for CQI calculation do not need to be updated continuously, but can be monitored by receiving a pager indicator channel (PICH) before switching to the Cell_FACH state. This will allow the WTRU to remain in an energy-saving state and only perform measurements when necessary.

[0051] Although the characteristics and elements are described in the preferred embodiments in specific combinations, each characteristic or element can be used alone, without the other characteristics and elements of the preferred embodiments or in various combinations with or without other characteristics and elements. The methods or flowcharts provided herein can be implemented in a computer program, software or firmware in tangible realization on a computer-readable storage medium for execution by a general purpose computer or processor. Examples of computer-readable storage media include read-only memory (ROM), random access memory (RAM), registry, cache memory, semiconductor memory devices, magnetic media such as internal hard drives and removable disks, magnetic media optical and optical media such as CDROM discs and digital versatile discs (DVDs).

[0052] Appropriate processors include, for example, a general purpose processor, special purpose processor, conventional processor, digital signal processor (DSP), a series of microprocessors, one or more microprocessors in

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15/15 association with a DSP core, controller, microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Portal Sets (FPGAs), any other type of integrated circuit (IC) and / or state machine .

[0053] A processor in association with software can be used to implement a radio frequency transceiver for use in a wireless transmission and reception unit (WTRU), user equipment (UE), terminal, base station, network controller, radio (RNC) or any host computer. The WTRU can be used in conjunction with modules, implemented in hardware and / or software, such as a camera, video camera module, videophone, headset, vibrating device, speaker, microphone, television transceiver, headset handsfree, keyboard, Bluetooth® module, radio frequency modulated (FM) unit, liquid crystal display unit (LCD), organic light-emitting diode (OLED) unit, digital music device, media, video game module, Internet browser and / or any wireless local area network (WLAN) module.

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Claims (12)

Claims 1. Method performed by a wireless transmission / reception unit (WTRU), the method comprising: - periodically send channel quality indicators (CQIs) through an uplink channel; - decode, through the WTRU, a transmission on a downlink control channel, the transmission being associated with a temporary radio network identifier (RNTI) from the WTRU; - determine, through the WTRU, that a wireless network is requesting the WTRU to send a CQI based on trigger criteria associated with the transmission on the downlink control channel; and - send, through the WTRU, the CQI to the wireless network. 2. Method, according to claim 1, characterized by the fact that the uplink channel is one of a shared channel, a common channel or a random access channel (RACH). 3. Method, according to claim 1, characterized by the fact that it also includes: send, through the WTRU to the wireless network, acknowledgments and negative acknowledgments through the uplink channel. 4. Method according to claim 1, characterized by the fact that the CQI is sent to the wireless network via an uplink channel. 5. Method according to claim 1, characterized by the fact that the downlink control channel is a shared channel. 6. Method according to claim 1, characterized by the fact that the RNTI is detected or received by the WTRU in the downlink control channel. 7. Wireless transmission and reception unit (WTRU) comprising: - a processor configured to periodically send, through a uplink channel, channel quality indicators (CQIs); - the processor further configured to decode a transmission on a downlink control channel, the transmission being associated with a temporary Petition 870190092060, of 16/09/2019, p. 29/33 2/2 WTRU radio network (RNTI); - the processor further configured to determine that a wireless network is requesting the WTRU to send a CQI based on a trigger criterion associated with the transmission on the downlink control channel; and - the processor is still configured to send the CQI to the wireless network. 8. WTRU, according to claim 7, characterized by the fact that the uplink channel is one among a shared channel, a common channel or a random access channel (RACH). 9. WTRU, according to claim 7, characterized by the fact that the processor is further configured to send negative acknowledgments and acknowledgments via the uplink CQI channel to the wireless network. 10. WTRU, according to claim 7, characterized by the fact that the processor is further configured to send the CQI through the uplink channel. 11. WTRU according to claim 7, characterized by the fact that the downlink control channel is a shared channel. 12. WTRU, according to claim 7, characterized by the fact that the processor is configured to detect or receive the RNTI in the downlink control channel. Petition 870190092060, of 16/09/2019, p. 30/33 1/4 102 104

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